Ferroelectric vapor deposition targets

ABSTRACT

The invention comprises ferroelectric vapor deposition targets and to methods of making ferroelectric vapor deposition targets. In one implementation, a ferroelectric physical vapor deposition target has a predominate grain size of less than or equal to 1.0 micron, and has a density of at least 95% of maximum theoretical density. In one implementation, a method of making a ferroelectric physical vapor deposition target includes positioning a prereacted ferroelectric powder within a hot press cavity. The prereacted ferroelectric powder predominately includes individual prereacted ferroelectric particles having a maximum straight linear dimension of less than or equal to about 100 nanometers. The prereacted ferroelectric powder is hot pressed within the cavity into a physical vapor deposition target of desired shape having a density of at least about 95% of maximum theoretical density and a predominate maximum grain size which is less than or equal to 1.0 micron. In one implementation, the prereacted ferroelectric powder is hot pressed within the cavity into a physical vapor deposition target of desired shape at a maximum pressing temperature which is at least 200° C. lower than would be required to produce a target of a first density of at least 85% of maximum theoretical density in hot pressing the same powder but having a predominate particle size maximum straight linear dimension of at least 1.0 micron at the same pressure and for the same amount of time, and a target density greater than the first density at the lower pressing temperature is achieved.

TECHNICAL FIELD

[0001] This invention relates to ferroelectric compositions, toferroelectric vapor deposition targets and to methods of makingferroelectric vapor deposition targets.

BACKGROUND OF THE INVENTION

[0002] Ferroelectric materials are a family of high K dielectricmaterials that are starting to become used more in the microelectronicsfabrication industry. In addition to having high dielectric constants,ferroelectric materials typically have low leakage current andnon-volatile data retention properties which make them attractive asdielectric materials for memory and transistor devices. Ferroelectricmaterials exhibit a number of unique and interesting properties. Onesuch property of a ferroelectric material is that it possesses aspontaneous polarization that can be reversed by an applied electricfield. Specifically, these materials have a characteristic temperaturecommonly referred to as the transition temperature, at which thematerial makes a structural phase change from a polar phase(ferroelectric) to a non-polar phase, typically called the paraelectricphase. Example ferroelectric materials include titanates and tantalates,such as by way of example only, lead lanthanum zirconium titanate(PLZT), barium strontium titanate (BST), and strontium bismuth tantalate(SBT).

[0003] As memory cell density and other circuitry density increases,there is a continuing challenge to maintain sufficiently high storagecapacitance in capacitors despite the decreasing size. Additionally,there is a continuing goal to further decrease capacitor size. Oneprincipal way of increasing cell capacitance is through cell structuretechniques. Yet as feature size continues to become smaller and smaller,development of improved materials for the cell dielectric becomeincreasingly important. Conventional non-ferroelectric dielectricmaterials, such as SiO, and Si₃N₄, are not expected to be suitable inmost application where device dimensions decrease to 0.25 micron inwidth because of the expected requirement for a very thin dielectricfilm. This is expected to apply in most all thin film dielectricmaterial applications.

[0004] In addition to use as transistor and capacitor dielectrics,ferroelectric materials might also be used in microelectronic mechanicalsystems. These devices are mechanical three-dimensional constructionswith sizes in the micrometer ranges. Sensors and actuators are exampletwo main categories of microelectronic mechanical systems. Ferroelectricthin films have been proposed for use with silicon-based microelectronicmechanical systems for both sensors and actuators in a variety ofapplications.

[0005] Thin film ferroelectric materials are known within the art to bedeposited by chemical vapor deposition, chemical solution deposition orphysical vapor deposition. Physical vapor deposition includessputtering, laser ablation, and other existing and to-be-developedmethods. Existing ferroelectric physical deposition targets aretypically made using conventional powder metallurgy with either coldpress sintering or hot pressing. Such prior methods can include theprovision of prereacted ferroelectric powders having individualparticles sized at greater than or equal to 1 micron. In hot pressing,such powders are consolidated by at high temperatures and pressure, andtypically results in targets having non-uniform grain sizes of from 1micron to 50 microns and non-uniform microstructure comprising multiplephases.

[0006] It would be desirable to improve upon existing ferroelectricphysical vapor deposition targets and their methods of manufacture.

SUMMARY

[0007] The invention comprises ferroelectric compositions, ferroelectricvapor deposition targets and methods of making ferroelectric vapordeposition targets. In one implementation, a ferroelectric physicalvapor deposition target has a predominate grain size of less than orequal to 1.0 micron, and has a density of at least 95% of maximumtheoretical density.

[0008] In one implementation, a method of making a ferroelectricphysical vapor deposition target includes positioning a prereactedferroelectric powder within a hot press cavity. The prereactedferroelectric powder predominately includes individual prereactedferroelectric particles having a maximum straight linear dimension ofless than or equal to about 100 nanometers. The prereacted ferroelectricpowder is hot pressed within the cavity into a physical vapor depositiontarget of desired shape having a density of at least about 95% ofmaximum theoretical density and a predominate maximum grain size whichis less than or equal to 1.0 micron.

[0009] In one implementation, the prereacted ferroelectric powder is hotpressed within the cavity into a physical vapor deposition target ofdesired shape at a maximum pressing temperature which is at least 200°C. lower than would be required to produce a target of a first densityof at least 85% of maximum theoretical density in hot pressing the samepowder but having a predominate particle size maximum straight lineardimension of at least 1.0 micron at the same pressure and for the sameamount of time, and a target density greater than the first density atthe lower pressing temperature is achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

[0011]FIG. 1 is a graph of pressure and temperature versus time forexemplary preferred processing in accordance with a methodical aspect ofthe invention.

[0012]FIG. 2 is a diagrammatic sectional view of a physical vapordeposition target adhered to a backing plate in accordance with but oneaspect of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] This disclosure of the invention is submitted in furtherance ofthe constitutional purposes of the U.S. Patent Laws “to promote theprogress of science and useful arts” (Article 1, Section 8).

[0014] The invention comprises a method of making a ferroelectricphysical vapor deposition target using hot pressing. A prereactedferroelectric powder is provided and positioned within a hot presscavity. In the context of this document, “prereacted” means that thematerial of the powder has previously been reacted to predominantlycomprise the substantial composition of what will be the finishedmaterial of the physical vapor deposition target being produced. Theprereacted ferroelectric powder predominately comprises individualprereacted ferroelectric particles having a maximum straight lineardimension of less than or equal to about 100 nanometers. Morepreferably, is at least 90% of the prereacted ferroelectric particleshave a maximum straight linear dimension of less than or equal to about100 nanometers, and even more preferably at least 98%. Further mostpreferably, any agglomeration of individual particles is preferably from0% to 10% by volume, with any agglomerated particles having a maximumstraight linear dimension which is less than 100 microns, and morepreferably from to 10 to 50 microns in maximum straight lineardimension.

[0015] Further preferably, the powder comprises substantially singlephase crystalline material, although multiphase crystalline materialsare contemplated. Also, a preferred maximum straight linear dimension ofthe individual prereacted ferroelectric particles is from about 10nanometers to about 50 nanometers, with a maximum size of around 30nanometers being most preferred.

[0016] The prereacted ferroelectric powder can also contain one or morevarious doping elements, preferably if included up to no more than 10 at%, for physical property or process improvement. Example elementsinclude lanthanum, calcium, niobium, strontium and bismuth, and mostpreferably to a doping level of from 2 at % to 5 at %.

[0017] By way of example only, one specific class of ferroelectricmaterials include (Ba_(1-x)Sr_(x))TiO₃, where x is from 0.0 to 1.0, andmore preferably where x is from 0.3 to 0.7. Another example includes(Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, where x is from 0.0 to 1.0, y isfrom 0.0 to 0.2, and z is from 0.0 to 0.1, and more preferably where xis from 0.3 to 0.7, y is from 0.05 to 0.15, and z is from 0.0 to 0.05.Further by of example only, another class includes(Sr_(1+y)Bi_(2+z))(T_(1-x)Nb_(x))₂O₉, where x is from 0.0 to 1.0, y isfrom −0.5 to 0.5, and z is from 0.0 to 0.8, and more preferably where xis from 0.3 to 0.7, y is from −0.3 to 0.3, and z is from 0.3 to 0.6.

[0018] Powders of the desired composition and particle size can befabricated using physical vapor condensation, chemical precipitation,combustion spray pyrolysis, and other methods. Such powders arecommercially available from ceramic powder vendors.

[0019] In one implementation, the prereacted ferroelectric powder is hotpressed within the cavity into a physical vapor deposition target ofdesired shape having a density of at least about 95% of maximumtheoretical density for the material, and a predominate maximum grainsize which is less than or equal to 1.0 micron. The target of desiredshape may or may not be subsequently configured into another shape.Further preferably, the hot pressing is conducted to form the target tohave at least 90% of its grains which are less than or equal to 1.0micron in maximum size. Even more preferably, the hot pressing isconducted to form the target to have a predominate portion, and morepreferably at least 90%, of its grains to have a maximum size of from0.3 micron to 0.75 micron. Further, the hot pressing preferably producesthe physical vapor deposition target to have a density of at least 99%of maximum theoretical density, more preferably greater than 99% maximumtheoretical density, and most preferably at least 99.5% of maximumtheoretical density.

[0020] The hot pressing is preferably done in a vacuum or inertatmosphere, with the resultant target possibly being somewhat reducedafter consolidation, resulting in an initially oxygen deficient target.Oxygen deficiency reduces the target electrical resistance, yet canresult in a higher film deposition rate. Any perceived oxygen deficiencywhich would otherwise occur in the deposited film can be compensated forby using, an appropriate oxygen partial pressure during film deposition,and in accordance with existing prior art or other to-be-developedmethods.

[0021] Temperature-pressure-time profiles for the hot pressing will belargely material dependent, and optimized by the fabricator. Examplepreferred processing conditions for barium strontium titanate include atemperature range of from 1100° C. to 1500° C., pressing time of from 30minutes to 60 minutes, and maximum pressing pressure ranging from 3000psi to 7000 psi. Example preferred processing conditions for leadlanthanum zirconium titanate include a pressing temperature of from 800°C. to 1100° C., pressing time from 30 minutes to 60 minutes, and maximumpressing pressure at from 3000 psi to 7000 psi. Example preferredprocessing conditions for strontium bismuth tantalate, with or withoutniobium, include pressing temperatures from 700° C. to 1100° C.,pressing time from 30 minutes to 60 minutes, and maximum pressingpressure ranging from 3000 psi to 7000 psi. Other conditions andmaterials are, of course, contemplated.

[0022] An exemplary preferred qualitative profile relationship fortemperature and pressure as a function of time for the hot pressing,generally regardless of material, is shown and described with respect toFIG. 1. A preferred first step is an initial pressure and temperatureramp to apply a preload temperature and pressure to the loose powder.The illustrated preferred second stage is constant preload pressure andcontinuing the temperature ramp. At this stage, volatile components inthe powder are continuously driven out of the powder compact. Apreferred third stage is a pressure and temperature ramp to the full andfinal highest conditions. Here, the powder compact starts to densify. Apreferred fourth stage is a constant pressure and constant temperatureto end the powder consolidation. A preferred fifth stage is atemperature and pressure release. At this stage, pressure is preferablycompletely removed, and heating reduced. A purpose is to achieve thefull density at the determined pressure and temperature, and to achievecontrolled cooling at a slow rate to prevent possible thermal shock andexcessive strain and stress in the target. A preferred sixth and finalstage is natural cooling, where heating is turned off and the targetcools naturally within the press/furnace.

[0023] In another considered aspect of the invention, the prereactedferroelectric powder is hot pressed within the cavity into a physicalvapor deposition target of desired shape at a maximum pressingtemperature which is at least 200° C. lower than would be required toproduce a target of a first density of at least 85% of maximumtheoretical density in hot pressing the same powder, but having apredominate particle size maximum straight linear dimension of at least1.0 micron at the same pressure and for the same amount of time. In thehot pressing in accordance with this aspect of the invention, a targetdensity greater than the first density at the lower pressing temperatureis achieved.

[0024] For example, the above-preferred embodiments for barium strontiumtitanate, lead zirconium titanate, and strontium bismuth niobiumtantalate show respective maximum pressing temperatures of 1500° C.,1100° C., and 1100° C., respectively. Prior art processing of the samematerials using prior art methods are understood to use a temperature atleast 200° C. higher than these indicated maximum preferred temperaturesutilizing a predominate powder particle size of 1.0 micron or greater,and results in achieving no more than 90% of maximum theoreticaldensity. In accordance with this aspect of the invention, a temperatureof at least 200° C. lower is utilized, vet a higher density is attained.

[0025]FIG. 2 illustrates a finished constructed target 20 adhered to abacking plate 22, to form a useable, finished target construction. Suchcan be fabricated by conventional or to-be-developed methods.

[0026] Processing in the above manner, and production of the resultanttarget, can improve efficiency in the microelectronics manufacture ofcircuitry and other components where physical vapor deposition rate,film uniformity and reduction of film particulate in the finished filmwill preferably occur. Preferably, targets with fine grain size of theinvention and high density will give high deposition rate and low filmparticulate, and result in a uniform and homogenous microstructure.Single phase nanopowders are preferably used, but several single phasepowders can be mixed and blended to achieve a desirable compositionprior to pressing. The powder is preferably not exposed to moistureprior to pressing to avoid undesired agglomeration.

[0027] Although the invention was principally motivated relative tofabrication of physical vapor deposition targets, the invention appliesas well to ferroelectric ceramic compositions and methods ofmanufacture.

EXAMPLE 1 Nanophase PLZT Targets

[0028] A specific reduction to practice example had the composition ofPb_(1.12)La_(0.05)(Zr_(0.40)Ti_(0.60))O_(x).

[0029] A precursor powder of single phasePb_(1.12)La_(0.05)(Zr_(0.40)Ti_(0.60))O_(x) was loaded into a graphitedie lined with graphoil. The die assembly was pre-compacted within thehot press chamber and evacuated to a vacuum of 1×10⁻³ Torr. The chamberwas then back-filled with ≧99% pure Argon to 507 Torr pressure.Subsequently, the hot press was heated to the sintering temperature(900° C.) at the rate of 300° C./h. Once peak temperature was reached,pressure was increased to 4 kpsi at the rate of 10 tons/minute. Thepowder compact was consolidated to high density under constanttemperature (900° C.) and pressure (4 kpsi) for 60-90 minutes. Followingconsolidation, the pressure was released and the temperature wasdecreased at the rate of 200° C./h. The heaters were turned off once thetemperature reached 700° C. The chamber was back-filled with Argon andallowed to cool to room temperature.

[0030] The target manufactured using the aforementioned process had adensity greater than or equal to 99.5% of the theoretical density (7.66g/cc). The microstructure was single phase with uniform composition andsub-micron grain size (0.5 μm). The resistivity was found to be 3×10¹⁰Ωcm, and the dielectric constant was 1000. The thermal conductivity andthe co-efficient of thermal expansion of the target was measured to be1.57 W/mK and 4.3×10⁻⁷/° C., respectively.

[0031] Another PLZT target was manufactured by the same process tocomprise Pb_(0.98)La_(0.22)(Zr_(0.39)Ti_(0.41))O_(x).

EXAMPLE 2 Nanophase BST Targets

[0032] A specific reduction to practice example had the composition ofBa_(0.50)Sr_(0.50)TiO_(x).

[0033] Nanophase Ba_(0.50)Sr_(0.50)TiO_(x) powder was loaded into agraphite die lined with graphoil. The die assembly was pre-compactedwithin the hot press chamber and evacuated to a vacuum of 1×10⁻³ Torr.The chamber was then back-filled with ≧99% pure Argon to 507 Torrpressure. Subsequently, the temperature was increased to the sinteringtemperature (1200° C.) at the rate 300° C./h. Maximum pressure (4 kpsi)was applied at the rate of 10 tons/minute when the temperature reached650° C. during the temperature ramp-up cycle. The powder compact wasconsolidated to high density under constant temperature (1200° C.) andpressure (4 kpsi) for 60 minutes following which the pressure wasreleased and the temperature was decreased at the rate of 200° C./h. Theheaters were turned off once the temperature reached 900° C. The chamberwas back-filled with Argon and allowed to cool to room temperature.

[0034] The target thus obtained had a density of 5.53 g/cc, or 98.3% ofits theoretical density. The microstructure is homogeneous withsub-micron grain size (<0.5 μm). Higher densities (>99% of theoreticaldensity) can be obtained by hot pressing at higher temperatures, at theexpense of significant grain growth. For example, a target has achieved100% of its theoretical density (5.6 g/cc), when hot pressed at 1400° C.In this case, the average grain size was 10 μm, significantly greaterthan the 0.5 μm obtained in a target hot pressed at 1200° C.

EXAMPLE 3 Nanophase SBT Targets

[0035] A specific reduction to practice example had the composition ofSr_(1.2)Bi_(2.4)Ta₂O_(x).

[0036] Nanophase Sr_(1.2)Bi_(2.4)Ta₂O_(x) powder was loaded into agraphite die lined with graphoil. The die assembly was pre-compactedwithin the hot press chamber and evacuated to a vacuum of 1×10⁻³ Torr.The chamber was then back-filled with ≧99% pure Argon to 507 Torrpressure. The hot press was then heated to the sintering temperature(850° C.) at the rate of 300° C./h. Once peak temperature was reached,pressure was increased to 4 kpsi at the rate of 10 tons/minute. Thepowder compact was consolidated to high density under constanttemperature (850° C.) and pressure (4 kpsi) for 60 minutes. Followingconsolidation, the pressure was released and the temperature wasdecreased at the rate of 200° C./h. The heaters were turned off once thetemperature reached 700° C. The chamber was back-filled with Argon andallowed to cool to room-temperature.

[0037] The density of the target was better than 99.5% of itstheoretical density. The microstructure was fairly uniform with some Biand Sr rich regions. The Bi and Sr rich regions can be attributed to thecomposition of the precursor powder, containing 20 mole % excess Bi andSr.

[0038] In compliance with the statute, the invention has been describedin language more or less specific as to structural and methodicalfeatures. It is to be understood, however, that the invention is notlimited to the specific features shown and described, since the meansherein disclosed comprise preferred forms of putting the invention intoeffect. The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A method of making a ferroelectric physical vapor deposition targetcomprising: positioning a prereacted ferroelectric powder within a hotpress cavity, the prereacted ferroelectric powder predominatelycomprising individual prereacted ferroelectric particles having amaximum straight linear dimension of less than or equal to about 100nanometers; and hot pressing the prereacted ferroelectric powder withinthe cavity into a physical vapor deposition target of desired shapehaving a density of at least about 95% of maximum theoretical densityand a predominate maximum grain size which is less than or equal to 1.0micron.
 2. The method of claim 1 wherein the powder comprises at least90% of prereacted ferroelectric particles having a maximum straightlinear dimension of less than or equal to about 100 nanometers.
 3. Themethod of claim 1 wherein the powder comprises at least 98% ofprereacted ferroelectric particles having a maximum straight lineardimension of less than or equal to about 100 nanometers.
 4. The methodof claim 1 wherein the powder comprises from 0% to 10% agglomeratedindividual particles, any agglomerated particles having a maximumstraight linear dimension which is less than 100 microns.
 5. The methodof claim 1 wherein the powder predominately comprises prereactedferroelectric particles having a maximum straight linear dimension offrom about 10 nanometers to about 50 nanometers.
 6. The method of claim1 wherein the powder comprises at least 90% of prereacted ferroelectricparticles having a maximum straight linear dimension of from about 10nanometers to about 50 nanometers.
 7. The method of claim 1 wherein thehot pressing is conducted to form the target to have at least 90% of itsgrains which are less than or equal to 1.0 micron in maximum size. 8.The method of claim 1 wherein the hot pressing is conducted to form thetarget to have at least 90% of its grains to have a maximum size from0.3 micron to 0.75 micron.
 9. The method of claim 1 comprising hotpressing to produce the physical vapor deposition target to have adensity of at least 99% of maximum theoretical density.
 10. The methodof claim 1 comprising providing the powder to be substantially singlephase crystalline material.
 11. The method of claim 1 comprisingproviding the powder to be multiple phase crystalline material.
 12. Themethod of claim 1 wherein the prereacted ferroelectric powder comprises(Ba_(1-x)Sr_(x))TiO₃, where x is from 0.0 to 1.0.
 13. The method ofclaim 1 wherein the prereacted ferroelectric powder comprises(Ba_(1-x)Sr_(x))TiO₃, where x is from 0.3 to 0.7.
 14. The method ofclaim 1 wherein the prereacted ferroelectric powder comprises(Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, where x is from 0.0 to 1.0, y isfrom 0.0 to 0.2, and z is from 0.0 to 0.1.
 15. The method of claim 1wherein the prereacted ferroelectric powder comprises(Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, where x is from 0.3 to 0.7, y isfrom 0.05 to 0.15 and z is from 0.0 to 0.05.
 16. The method of claim 1wherein the prereacted ferroelectric powder comprises(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.0 to 1.0, y isfrom −0.5 to 0.5, and z is from 0.0 to 0.8.
 17. The method of claim 1wherein the prereacted ferroelectric powder comprises(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.3 to 0.7, y isfrom −0.3 to 0.3, and z is from 0.3 to 0.6.
 18. The method of claim 1wherein the prereacted ferroelectric powder comprises one of bariumstrontium titanate, lead zirconium titanate, and strontium bismuthtantalate having a total of up to 10 at % of one of more doping elementsof lanthanum, calcium, niobium, strontium and bismuth.
 19. The method ofclaim 1 wherein the prereacted ferroelectric powder comprises one ofbarium strontium titanate, lead zirconium titanate, and strontiumbismuth tantalate having a total of from 2.0 at % to 5.0 at % of one ofmore doping elements of lanthanum, calcium, niobium, strontium andbismuth.
 20. A method of making a ferroelectric physical vapordeposition target comprising: positioning a prereacted ferroelectricpowder within a hot press cavity, the prereacted ferroelectric powderpredominately comprising individual prereacted ferroelectric particleshaving a maximum straight linear, dimension of from about 10 nanometersto about 50 nanometers; and hot pressing the prereacted ferroelectricpowder within the cavity into a physical vapor deposition target ofdesired shape having a density of at least about 99% of maximumtheoretical density and at least 90% of its grains to have less than orequal to 1.0 micron in maximum size.
 21. The method of claim 20 whereinthe prereacted ferroelectric powder comprises (Ba_(1-x)Sr_(x))TiO₃,where x is from 0.0 to 1.0.
 22. The method of claim 20 wherein theprereacted ferroelectric powder comprises (Ba_(1-x)Sr_(x))TiO₃, where xis from 0.3 to 0.7.
 23. The method of claim 20 wherein the prereactedferroelectric powder comprises (Pb_(1+y),La_(z))(Zr_(1-x)Ti_(x))O₃,where x is from 0.0 to 1.0, y is from 0.0 to 0.2, and z is from 0.0 to0.1.
 24. The method of claim 20 wherein the prereacted ferroelectricpowder comprises (Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, where x is from 0.3to 0.7, y is from 0.05 to 0.15 and z is from 0.0 to 0.05.
 25. The methodof claim 20 wherein the prereacted ferroelectric powder comprises(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.0 to 1.0, y isfrom −0.5 to 0.5, and z is from 0.0 to 0.8.
 26. The method of claim 20wherein the prereacted ferroelectric powder comprises(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.3 to 0.7, y isfrom −0.3 to 0.3, and z is from 0.3 to 0.6.
 27. The method of claim 20wherein the powder comprises at least 90% of prereacted ferroelectricparticles having a maximum straight linear dimension of from about 10nanometers to about 50 nanometers.
 28. A method of making aferroelectric physical vapor deposition target comprising: positioning aprereacted ferroelectric powder within a hot press cavity, theprereacted ferroelectric powder predominately comprising individualprereacted ferroelectric particles having a maximum straight lineardimension of less than or equal to about 100 nanometers; and hotpressing the prereacted ferroelectric powder within the cavity into aphysical vapor deposition target of desired shape at a maximum pressingtemperature which is at least 200° C. lower than would be required toproduce a target of a first density of at least 85% of maximumtheoretical density in hot pressing the same powder but having apredominate particle size maximum straight linear dimension of at least1.0 micron at the same pressure and for the same amount of time, andachieving a target density greater than the first density at the lowerpressing temperature.
 29. The method of claim 28 wherein the prereactedferroelectric powder comprises (Ba_(1-x)Sr_(x))TiO₃, where x is from 0.0to 1.0, and the maximum pressing temperature is less than or equal toabout 1500° C.
 30. The method of claim 28 wherein the prereactedferroelectric powder comprises (Ba_(1-x)Sr_(x))TiO₃, where x is from 0.0to 1.0, and the maximum pressing temperature is from about 1100° C. toabout 1500° C., and at a maximum pressing pressure between about 3000psi and 7000 psi.
 31. The method of claim 28 wherein the prereactedferroelectric powder comprises (Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, wherex is from 0.0 to 1.0, y is from 0.0 to 0.2, and z is from 0.0 to 0.1,and the maximum pressing temperature is less than or equal to about1100° C.
 32. The method of claim 28 wherein the prereacted ferroelectricpowder comprises (Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, where x is from 0.0to 1.0, y is from 0.0 to 0.2, and z is from 0.0 to 0.1, and the maximumpressing temperature is from about 800° C. to about 1100° C., and at amaximum pressing pressure between about 3000 psi and 7000 psi.
 33. Themethod of claim 28 wherein the prereacted ferroelectric powder comprises(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.0 to 1.0, y isfrom −0.5 to 0.5, and z is from 0.0 to 0.8, and the maximum pressingtemperature is less than or equal to about 1100° C.
 34. The method ofclaim 28 wherein the prereacted ferroelectric powder comprises(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.0 to 1.0, y isfrom −0.5 to 0.5, and z is from 0.0 to 0.8, and the maximum pressingtemperature is from about 700° C. to about 1100° C., and at a maximumpressing pressure between about 3000 psi and 7000 psi.
 35. The method ofclaim 28 wherein the powder predominately comprises prereactedferroelectric particles having a maximum straight linear dimension offrom about 10 nanometers to about 50 nanometers.
 36. The method of claim28 wherein the powder comprises at least 90% of prereacted ferroelectricparticles having a maximum straight linear dimension of from about 10nanometers to about 50 nanometers.
 37. A ferroelectric physical vapordeposition target comprising a predominate grain size of less than orequal to 1.0 micron and having a density of at least 95% of maximumtheoretical density.
 38. The ferroelectric physical vapor depositiontarget of claim 37 comprising a density of at least 99% of maximumtheoretical density.
 39. The ferroelectric physical vapor depositiontarget of claim 37 comprising a density of greater than 99% of maximumtheoretical density.
 40. The ferroelectric physical vapor depositiontarget of claim 37 comprising a density of at least 99.5% of maximumtheoretical density.
 41. The ferroelectric physical vapor depositiontarget of claim 37 wherein at least 90% of the grains have a maximumsize of less than or equal to 1.0 micron.
 42. The ferroelectric physicalvapor deposition target of claim 37 wherein at least 90% of the grainshave maximum size of less than 1.0 micron.
 43. The ferroelectricphysical vapor deposition target of claim 37 having a predominate grainmaximum size of from 0.3 micron to 0.75 micron.
 44. The ferroelectricphysical vapor deposition target of claim 37 wherein at least 90% of thegrains have a maximum size of from 0.3 micron to 0.75 micron.
 45. Theferroelectric physical vapor deposition target of claim 37 wherein atleast 95% of the grains have a maximum size of from 0.3 micron to 0.75micron.
 46. The ferroelectric physical vapor deposition target of claim37 wherein at least 99% of the grains have a maximum size of from 0.3micron to 0.75 micron.
 47. The ferroelectric physical vapor depositiontarget of claim 37 predominately comprising (Ba_(1-x)Sr_(x))TiO₃, wherex is from 0.0 to 1.0.
 48. The ferroelectric physical vapor depositiontarget of claim 37 predominately comprising (Ba_(1-x)Sr_(x))TiO₃, wherex is from 0.3 to 0.7.
 49. The ferroelectric physical vapor depositiontarget of claim 37 predominately comprising(Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, where x is from 0.0 to 1.0, y isfrom 0.0 to 0.2, and z is from 0.0 to 0.1.
 50. The ferroelectricphysical vapor deposition target of claim 37 predominately comprising(Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, where x is from 0.3 to 0.7, y isfrom 0.05 to 0.15 and z is from 0.0 to 0.05.
 51. The ferroelectricphysical vapor deposition target of claim 37 predominately comprising(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.0 to 1.0, y isfrom −0.5 to 0.5, and z is from 0.0 to 0.8.
 52. The ferroelectricphysical vapor deposition target of claim 37 predominately comprising(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.3 to 0.7, y isfrom −0.3 to 0.3, and z is from 0.3 to 0.6.
 53. The ferroelectricphysical vapor deposition target of claim 37 comprising one of bariumstrontium titanate, lead zirconium titanate, and strontium bismuthtantalate having a total of up to 10 at % of one of more doping elementsof lanthanum, calcium, niobium, strontium and bismuth.
 54. Theferroelectric physical vapor deposition target of claim 37 comprisingone of barium strontium titanate, lead zirconium titanate, and strontiumbismuth tantalate having a total of from 2.0 at % to 5.0 at % of one ofmore doping elements of lanthanum, calcium, niobium, strontium andbismuth.
 55. A ferroelectric ceramic composition comprising apredominate grain size of less than or equal to 1.0 micron and having adensity of at least 95% of maximum theoretical density.
 56. Theferroelectric ceramic composition of claim 55 comprising a density of atleast 99% of maximum theoretical density.
 57. The ferroelectric ceramiccomposition of claim 55 comprising a density of greater than 99% ofmaximum theoretical density.
 58. The ferroelectric ceramic compositionof claim 55 comprising a density of at least 99.5% of maximumtheoretical density.
 59. The ferroelectric ceramic composition of claim55 wherein at least 90% of the grains have a maximum size of less thanor equal to 1.0 micron.
 60. The ferroelectric ceramic composition ofclaim 55 wherein at least 90% of the grains have maximum size of lessthan 1.0 micron.
 61. The ferroelectric ceramic composition of claim 55having a predominate grain maximum size of from 0.3 micron to 0.75micron.
 62. The ferroelectric ceramic composition of claim 55 wherein atleast 90% of the grains have a maximum size of from 0.3 micron to 0.75micron.
 63. The ferroelectric ceramic composition of claim 55 wherein atleast 95% of the grains have a maximum size of from 0.3 micron to 0.75micron.
 64. The ferroelectric ceramic composition of claim 55 wherein atleast 99% of the grains have a maximum size of from 0.3 micron to 0.75micron.
 65. The ferroelectric ceramic composition of claim 55predominately comprising (Ba_(1-x)Sr_(x))TiO₃, where x is from 0.0 to1.0.
 66. The ferroelectric ceramic composition of claim 55 predominatelycomprising (Ba_(1-x)Sr_(x))TiO₃, where x is from 0.3 to 0.7.
 67. Theferroelectric ceramic composition of claim 55 predominately comprising(Pb_(1+y)La_(x))(Zr_(1-x)Ti_(x))O₃, where x is from 0.0 to 1.0, y isfrom 0.0 to 0.2, and z is from 0.0 to 0.1.
 68. The ferroelectric ceramiccomposition of claim 55 predominately comprising(Pb_(1+y)La_(z))(Zr_(1-x)Ti_(x))O₃, where x is from 0.3 to 0.7, y isfrom 0.05 to 0.15 and z is from 0.0 to 0.05.
 69. The ferroelectricceramic composition of claim 55 predominately comprising(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.0 to 1.0, y isfrom −0.5 to 0.5, and z is from 0.0 to 0.8.
 70. The ferroelectricceramic composition of claim 55 predominately comprising(Sr_(1+y)Bi_(2+z))(Ta_(1-x)Nb_(x))₂O₉, where x is from 0.3 to 0.7, y isfrom −0.3 to 0.3, and z is from 0.3 to 0.6.
 71. The ferroelectricceramic composition of claim 55 comprising one of barium strontiumtitanate, lead zirconium titanate, and strontium bismuth tantalatehaving a total of up to 10 at % of one of more doping elements oflanthanum, calcium, niobium, strontium and bismuth.
 72. Theferroelectric ceramic composition of claim 55 comprising one of bariumstrontium titanate, lead zirconium titanate, and strontium bismuthtantalate having a total of from 2.0 at % to 5.0 at % of one of moredoping elements of lanthanum, calcium, niobium, strontium and bismuth.